[kernel][timer] Change timer callbacks to return void

Following recent changes, all of the timer callbacks now always return
INT_NO_RESCHEDULE. We can therefore remove the return values. We can
change the timer callbacks to return void instead of "enum
handler_return".

ZX-1490

Change-Id: Idb42c52c1daec599ffb16d5862048d57f520db0f

[kernel] Cleanup: Refer to "timer_t" rather than "struct timer" for consistency

ZX-1490

Change-Id: I653b55552c901ad5ee43fb3ba3826b51a01038d1

[kernel][time] Prefer zx_{time,duration}_t to lk_time_t

Change-Id: Ie219c61f2ba7fd073917a6738221e2dde969fc2d

[kernel][time] Prefer ZX_TIME_INFINITE to INFINITE_TIME

Change-Id: I057f13706d3b4f4d735a4a4f1a6b5a8319a9c4c4

[zx] Magenta -> Zircon

The Great Renaming is here!

Change-Id: I3229bdeb2a3d0e40fb4db6fec8ca7d971fbffb94

[kernel][status] Convert the rest of kernel/lib to mx_status_t

Change-Id: Iba1bb7024bcefa7c5e3ee58b02d0be758c6545ae

[kernel][timer] Rename timer_initialize to timer_init.

Also rename timer_init to timer_queue_init.

Change-Id: Ie33f61d4570087ad97383ed0e69c7194d09b0ef8

[kernel][lib] Use the new MX_OK and MX_ERR_* names

Change-Id: I436bb0728838729bef6e20a6db0e8ce6a96b5534

[kernel][time] Rename lk_bigtime_t and current_time_hires()

Now that millisecond time is gone from the kernel, reclaim the names
used for it.

lk_bigtime_t -> lk_time_t
current_time_hires() -> current_time()

Change-Id: I7db5de01171096c04a2b12d293e047e6a08a0aef

[kernel][time] Switch timeout interfaces to deadlines

This switches all kernel primitives to using deadlines with respect
to the monotonic clock instead of relative nanosecond timeouts.

The only remaining time interface that is not on deadlines is
thread_sleep.

Change-Id: Ibfb4e7a0673ecb5740dba33ee9d056f668e27256

[kernel][time] Switch kernel to nanoseconds internally

A subsequent diff will rename lk_bigtime_t to lk_time_t and
current_time_hires() to current_time().

Change-Id: Ied15e687714f784e2180aac59c8e0813c83bfcd0

[system] Merge kernel compiler.h with global compiler.h

Change-Id: Ia9f35fdb5321c82a3f844510ca93aada81d2f8c9

[magenta] Initial commit